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    <title>ShellCheck: SC2077 – You need spaces around the comparison operator.</title>
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    <h1>SC2077 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC2077">See this page on GitHub</a>
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    <h2 id="you-need-spaces-around-the-comparison-operator">You need spaces
around the comparison operator.</h2>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC2077.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="kw">[[</span> 0=1 <span class="kw">]]</span></span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC2077.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="kw">[[</span> 0 <span class="ot">=</span> 1 <span class="kw">]]</span></span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p><code>[[ 0 = 1 ]]</code> means "check if 0 and 1 are equal".</p>
<p><code>[[ str ]]</code> is short form for <code>[[ -n str ]]</code>,
and means "check if <code>str</code> is non-empty". It doesn't matter if
<code>str</code> happens to contain <code>0=1</code>.</p>
<p>Always use spaces around the comparison operator in <code>[..]</code>
and <code>[..](..)</code>, otherwise it won't be recognized as an
operator.</p>
<h3 id="exceptions">Exceptions</h3>
<p>None.</p>
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